Life expectancy in the U.S. has fallen slightly, according to a new government report.

The life expectancy for a baby born in 2008 is 77.8 years, down from 2007’s all-time-high of 77.9 years.

Life expectancy for Americans generally has increased steadily since 1975, but the numbers dipped in 1993 and again in 2005.

The report’s lead author, Arialdi Minino, characterized the decline as tiny, and said it would take years of data to determine if it is the start of a downward trend, the Associated Press reports.

On a happier note, the infant mortality rate fell from 6.75 infant deaths per 1,000 live births to 6.59, a drop Minino called “pretty significant,”  HealthDay reports. Still, the mortality rate for black infants remained about twice that of whites.

The government figures showed that the gap in life expectancy between blacks and whites in the U.S. narrowed to 4.6 years. In 2008, the average lifespan edged down to 75.3 years for white men and to 80.3 for white women. For black women it remained unchanged at 76.8 years, while the average lifespan for black men hit a record high of 70.2 years.

For the first time in 50 years, chronic respiratory diseases like asthma and emphysema replaced stroke as the third-leading cause of death.

Nearly half of all deaths in the U.S. stemmed from heart disease and cancer, which remained the two leading killers.

Minino cautioned that the report was not designed to find the reasons for the mortality changes, and that the increase in deaths from chronic respiratory diseases could be related to revisions in the way some deaths are classified.

The report was released by the National Center for Health Statistics, part of the Centers for Disease Control and Prevention.